The application of a modified Perl's stain in conjunction with a diaminobenzidine method has revealed fine details regarding the location of brain iron that were heretofore unknown. The iron is seen to occur in granules, amorphorous accumulations, and fiber-like processes in glial cells and neurons. There appears to be an intersting correlation between (1) the high concentration of iron in structures known to have a high content of GABA (globus pallidus and substantia nigra) and (2) the distribution of iron in sites in which neuroactive peptides have been localized, including the tuberal region of the hypothalamus.